• Background
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Whereas the Gestalt psychologists emphasized organization, other research has emphasized the bottom-up approach—that is, how we use the information in the world to construct a percept of what we see. One of the most influential bottom-up theories advanced to account for object recognition was developed by Irving Biederman in the 1980s (see Biederman, 1987). In this view, the complexity of object recognition is solved when the visual system breaks down objects into the environment into what Biederman called geometric ions or geons. Geons represent the basic units of objects and consist of simple shapes, such as cylinders and pyramids. Recognition-by-components theory states that object recognition occurs by representing each object as a combination of basic units (geons) that make up that object. We recognize an object by the relation of the geons. Biederman tentatively proposed that there were roughly independent geons and that just about any object could be represented by some combination of these geons.

In this illustration, see if you can identify some of the geons that make up objects. If you have a slow connection and not all the images load, just reload the page, and that usually works. You might need to go full screen before reloading the page.


Full Screen Mode

To see the illustration in full screen, which is recommended, press the Full Screen button, which appears at the top of the page.

Illustration Tab


Below is a list of the ways that you can alter the illustration. The settings include the following:

1-5: these are the geons that might be in the image you are examining.
Check Answers: it brings up the same image with the geons that make up the image shown. It only works if you have selected at least one geon that might be in the image.
New Image: it picks a new image to examine. It only works if you have checked your answers for the image currently being shown.


Pressing this button restores the settings to their default values.